Title :
Detecting mode hopping in semiconductor lasers by monitoring intensity noise
Author :
Heumier, T.A. ; Carlsten, J.L.
Author_Institution :
Dept. of Phys., Montana State Univ., Bozeman, MT, USA
fDate :
11/1/1993 12:00:00 AM
Abstract :
Mode-hopping semiconductor lasers exhibit intensity fluctuations which are correlated to the level of mode-hopping activity. It is shown that these fluctuations occur at a level that is easily measured and that mode hopping can be detected with a p-i-n photodiode and an AC voltmeter having microvolt sensitivity. A plot of intensity fluctuations versus laser case temperature and injection current displays periodicities in the conditions under which mode hopping occurs. These regularities are explained in terms of the peak gain wavelength passing the longitudinal mode wavelength as temperature changes. The occurrence of mode hopping is determined by junction temperature (which determines the relationship of the gain peak with longitudinal mode structure) and injection current (which determines mode-hopping frequency). The junction temperature is itself a function of case temperature and injection current. The stability map shows that precise control of the operating parameters is not sufficient to avoid mode hopping. It is necessary to have these parameters set properly
Keywords :
laser modes; semiconductor device noise; semiconductor lasers; AC voltmeter; gain peak; injection current; intensity fluctuations; intensity noise monitoring; junction temperature; laser case temperature; longitudinal mode structure; microvolt sensitivity; mode hopping detection; mode-hopping activity; operating parameters; p-i-n photodiode; semiconductor lasers; stability map; Displays; Fluctuations; Frequency; Laser modes; Monitoring; PIN photodiodes; Semiconductor lasers; Stability; Temperature sensors; Voltmeters;
Journal_Title :
Quantum Electronics, IEEE Journal of